Pivotal mounting for aircraft wheels



Jan. 9, 1951 R. w. BROWN 2,537,634

PIVOTAL MOUNTING FOR AIRCRAFT WHEELS Filed Sept. 13, 1946 7 Sheets-Sheet l ATTORNEYS Jan. 9, 1951 R. w. BROWN 2,537,634

PIVOTAL MOUNTING FOR AIRCRAFT WHEELS Filed Sept. 15, 1946 7 Sheets-Sheet 2 INVENTOR QOYWBEOWN ATTORNEYS Jan. 9, 1951 R. w. BROWN PIVOTAL MOUNTING FOR AIRCRAFT WHEELS '7 Sheets-Sheet 5 Filed Sept. 13, 1946 INVENTOR ROY wmzowu BY 5 ATTORNEYS Jan. 9, 1951 R. w. BROWN 2,537,634

PIVOTAL MOUNTING FOR AIRCRAFT WHEELS Filed Sept. 15, 1946 7 Sheets-Sheet 4 H a w 22 f 44 I I E! H I I 26 I I 25 25 z;

I NVENTOR ATTORNEYS Jan. 9, 1951 R. w. BROWN PIVOTAL MOUNTING FOR AIRCRAFT WHEELS 7 Sheets-Sheet 5 Filed Sept. 13, 1946 INVEN' 'I'OR 320v w. mow/q 5- K wrroanavs R. w. BROWN 2,537,634

Jan. 9, 1951 PIVOTAL MOUNTING FOR AIRCRAFT WHEELS 7 Sheets-Sheet 6 Filed Sept. 13, 1946 IN V E NTOR 'IZOYWBTZOWN ATTORNEYS Jan. 9, 1951 R. w. BROWN PIVOTAL MOUNTING FOR AIRCRAFT WHEELS 7 Sheets-Sheet 7 Filed Sept. 15, 1946 l N VENTOR,

QOYWBQOWN 5% l A 7' 1- o R N E. Y s

lllll Patented Jan. 9, 1951 4:- .1- 1:

PIVOTAL MOUNTING FOR AIRCRAFT WHEELS Roy W. Brown, Akron, Ohio, assignor to The Firestone Tire & Rubber Company, Akron, Ohio, a corporation of Ohio Application September 13, 1946, Serial No. 696,884

the invention;

3 Claims. (01. 244 s) This invention relates to aircraft undercarriages and has for its general object the provision of an inexpensive aircraft undercarriage which is light in weight and adaptable for use with different sized and weight planes.

Another object of the invention is to provide an aircraft undercarriage which has desirable taxiing and shock absorbing characteristics.

Another object of the invention is to provide an aircraft undercarriage which has a large safety factor and which permits a large wheel movement under load.

A further object of the invention is to provide a novel shock absorption unit utilizing a rubber sleeve support member.

Yet another object of the invention-is to pro-' vide a reenforced rubber sleeve as a load carrying member.

Another object of the invention is to provide an enclosed rubber sleeve support member which can be combined with a compressed fluid for forces applied thereto; to provide a novel type of friction material covered rubber thrust ring having a reenforcing ring therein; to provide a threaded bushing with a seat portion thereon to aid in forming a rigid mount on a suspension beam for an aircraft wheel shaft; and to provide a novel lock pin and securing means for retaining a shaft locked to a support arm.

The foregoing and other objects and advantages of the invention will be made apparent as the specification proceeds.

Attention now is directed to the accompanying drawings, wherein:

Fig. 1 is a side elevation of an airplane having an undercarriage embodying the principles of the invention;

Fig. 2 is a front elevation of the airplane of Fig. 1;

Fig. 3 is an elevation of an airplane showing a difierent type assembly of the undercarriage of Fig. 4 is an enlarged elevation, partly in section, of the undercarriage unit alone;

Fig. 513 a fragmentary section of the absorption unit of the invention before it is completely assembled;

Fig. 6 is a side elevation of the undercarriage unit of Fig. 4, with the extreme positions of the wheel being indicated in dotted lines;

Figs. 7, 8 and 9 are sections, similar to Fig. 5,

of the unit under no or normal load, part load,

and greater load, respectively;

Fig. 10is an enlarged vertical section on line l0l0 of Fig. 5;

Fig. 11 is a fragmentary enlarged side elevation of the connection of the support tube and the suspension beam of the invention;

Fig. 12 is a longitudinal section on line |2- l2- of Fig. 11;

Fig. 13 is a transverse section on line l3-l3 of Fig. 12; I

Fig. 14 is a partially exploded view of the mounting pin assembly for the suspension beam;

Fig. 15 is a section on line l5|5 of Fig. 11;

Fig. 16 is a fragmentary section of the suspension arm and wheel mounting shaft on line l6l6 oiFig.4; v

Fig. 17 is a fragmentary longitudinal section of a modified type of a mounting arm for the suspension beam;

Fig. 18 is a transversesection on line Iii-l8 of Fig. 17;

Fig. 19 is an elevation of a modified type of undercarriage unit of the invention;

- Fig. 20 is a side elevation of the undercarriage unit of Fig. 19; and

Fig. 21 is an enlarged vertical section on line 2 l2l of Fig. 19.

Referring in detail to the construction shown in the drawings, an airplane l of conventional design is provided with a plurality of undercarriage units, indicated generally by the numeral 2, which support the airplane and absorb the land? ing impacts thereof. In Fig. 2, the units 2 at the front of the plane are shown as connecting toand being supported by cantilever arms 3 which are suitably secured to the" airplane, while the tail undercarriage unit is directly secured to the fuselage of the plane.

Fig. 3 shows a different mounting for the units- 2- which are in this instance secured to the wings 4 of an airplane I but it will be realized that any desired mounting structure may be used with the undercarriage units of the invention.

Aircraft undercarriages obviously are subjected to severe impacts on landings and in general must be sturdily constructed. To this end, the units 2 each support a wheel 5, carrying a pneumatic tire 6, by a substantially U-shaped load carrying, or suspension beam '1 that is pivotally carried by a hollow rectangular bracket 8 that is welded or otherwise secured to and eccentrically extends from the lower end of a vertically positioned support tube 9. The Wheels are mounted on shafts It that have threaded portions i l formed thereon at their ends.

A feature of the invention is that a substantially rigid beam construction is provided for the free ends of the suspension beam 1 and this result is achieved partly by tapped lock or bushing members l2 and l2 which engage with the threads H on the ends of the shaft H]. The

members 12 and lil have at least a pair of pardraw the shaft tightly between the ends of the" beam and form a strong shock-resistant, loadcarrying member therefrom. Each arm of the suspension beam 1 is formed, preferably, from a stamped metal part and ordinarily the beam is formed from two stamped members that are welded together in back to back relation, as indicated in Fig; 4; A reen'forcing plate [6 may be welded to the inturned flanges of the beam sections to reenforce them while inwardly turned lugs 11 of any suitable length may be welded together at their edges to form a closed hollow section in the beam arm. A reenforci'ng channel 18 may be formed in the arms of the beam 1' for further strengthening the arm' so that it can be made from light gauge material.

A prime feature of the invention is that the shock, or impact, absorption unit of the invention utilizes both a rubber distort on and air compression action for absorption of load. An-elongated rubber sleeve l9, which is relatively thick walled and which is made from relatively stiff, high strength rubber, is received in the tube 9 for'telescopin movement therein. The sleeve [9 is made of a plurality of annular sections having concave outer surfaces and convex inner surfaces, as shown in Fig. 5. Rings 2|, which are T-shaped in radial section; are positioned between and integrally bonded to'the rubber sleeves at the radially inner legs of the rings. The rings 2| are metallic and suitably processed so as to have good adhesion with the rubber sleeve and the rings seem to reenforce the sleeves against buckling when loaded. The rings 2| and rubber sections 2B are assembled in desired form and then are integrally bonded. together by vulcanization. The top or radially outer parts of the rings 2i are flush with or preferably extend slightly radially beyond the periphery of the'sleeve [9' and friction material covers 22 are shown as being secured to these rings. This friction material 22 comprises fabric that is impregnated with a thixotropic lubricating composition. which gives" the material the unusual characteristicof great-i.

er kinetic coefficient of friction than static coefficient of friction. One example of such lubricant composition is made of castor oil, a wax compatible with the oil, and an alumimnn soap uniformly dispersedin the composition. Graphite also may be present in the composition.

The upper end of the support tube!) is closed by a cap 23 that is suitably secured thereto while a bottom cap 24 is secured to the lower end of the sleeve l9 in any suitable manner, as by vulcanization. A connector tube 25 is secured, as by a weld, to the cap 24 while a stop collar 26 is fixed in the lower end of the tube 9 to limit downward motion of the rubber sleeve l9 after the sleeve is telescoped into engagement with the support tube and the collar 26 is secured in position. In setting up the absorption unit, it normally is helpful to make the rubber sleeve of such size that it must be compressed or stressed in order to get it into position in a support tube. A rubber washer 21 may be carried by the lower surface of the cap 25 to cushion it when it contacts the collar 26.

It also is very helpful in adapting the undercarriage unitsof the invention to carry any of a variety of loads, to use air pressure in the tube 9 to aid in load support. Thus the tube 9 must be air tight and a fitting 90 is positioned in the tube Wall for connection to" suitable air pressuresupply'means. For example, by varying the pressure in the tube from a low of 300'pounds per square inch to a high of 1200 pounds per square inchthe load supported by the absorption unit 'can'be widely varied;

The connector tube 25 is welded, preferably,

at its lower end to a relatively 1ong,"thin bracket- 2 8 which is positioned in, or parallel to the plane'of rotation of the wheel 5.

The bracket 28 has a reduced thickness section 29 extending longitudinally thereof, as shown in' Fig. 10, so that the bracket is strong in its general direction of load application but is slight-- 1y flexible in a direction transverse thereto. The foot or lower end 23 of the bracket 28 has a hole 30 therein which has a shaft or pin 1H,. carrying bearings 32 and 33, extending therethrough. Thepin 3! may be tubular to reduce its Weight and it is secured at its ends in aligned housings 34 that are secured to the suspension beam I by bolts 35. The bracket 28 may be welded to the bearing 32 which is rotatably carried by the bearing 33.

The support end of the suspension beam 1 is pivotally secured to the bracket 8 by a pi'n'36 which has threaded sections 31 formed at the ends thereof with the threads on such sections 31 extending in the same direction. The beam 1 has bosses 38 formed on its opposite sides at its ends and tapped bearings 39are positioned in the bosses '38, being secured in place by flaring or peening theirouterends over the adjacent beam sections and by conventional deviceasuch as rivets, that extend through the beam 7 and flanges H of the bearings 39. The bracket 8 is provided with bearing 42 and 43 that are suit' ably secured thereto and have tapped "bores through which the pin extends and engages by the threaded sections 31. The bearing 53 has a tapered or conical end portion 46 which has a counterbore 45 formed at such end as shown-in- Fig. 14. Then a U shaped lock pin as isprovided to' engage with parallel flattened sections 41 formed on opposite sides of the pin 36. An

.8. Axially extending slots 50, which are. circum;

as described hereinbefore.

ferentially spaced, are formed "in the outer co rner of the nut 48 for engagement with lugs on a tool for loosening'or tightening the nut 48. The pin 36 is positioned by threading it through. the left hand bearings 39 and 42 into the beam 8 where the lock nut 43 1s held and the pin 35 then is threaded through such nut 38 and through the other bearings 33, and 43. As shown, the pin 36 maybe tubular and have end covers 5| secured thereto by a bolt 52 that extends through the pin.

In a modification of the suspension beam shown in Figs. 17 and 18, the suspension beam arms 60 are provided with integral end flanges 6| that extend inwardly therefrom for engagement with the ends of the lock members which are used to mount the wheel support shafts. Thus the use of the separate plates, as the plates H! in Fig. 4 is avoided. A reenforcing rib 62 may be formed on the arms 60.

Another embodiment of the invention wherein the undercarriage is free to pivot as a castor, is shown in Figs. 19 through 21. In these figures, the support tube 9 is similar to the tube 9 and carries the same wheel and load support means The tube 9 has a short tube 1! having a flange H formed at its upper end, suitably secured to it adjacent its upper end while a housing or tube 12 is positioned in spaced encompassing relation to the tube. Suitable devices, such as rubber sleeves 13 having friction material covers 74 and metal backing plates 15 are positioned between the tubes 9 and 12 to retain them in aligned association and to prevent too free relative movement therebetween. A load support flange I6 is formed at the'lower .end of the tube 12 and a split lock ring or collar TI is positioned over the flanges II and 16 to secure them together and to transmit tensional load therebetween. An annular flat rubber thrust collar 18 is placed between the flanges H and 16 and it may have a flat metal thrust bearing 19 embedded therein. As another feature of the invention, a cover of friction material 80 may be provided on the lower surface of the bearing 18 to aid in damping tensional movement of the suspension unit. A pair of diametrically spaced mounting arms 8! are secured to the tube 12 and extend upwardly and outwardly therefrom and they have reenforcing members 82 secured therebetween, which arms 8| may be engaged in any desired manner with the aircraft on which the undercarriage is to be mounted. If desired, a tube 83 may be positioned in the tube 12 on the axis of such tube to connect to the rubber sleeve (not shown) in the tube 9 for controlling the air pressure therein.

From the foregoing, it will be seen that a sturdy undercarriage unit is provided that can be used on any of a number of airplanes dependent upon the initial load conditions of the load absorption unit. The appreciably greater movement of the pneumatic tire and wheel than that of the load absorbing unit aids in giving desired properties to the support unit.

It will be realized that the load absorption unit and rubber sleeve of the invention may be used in any desired load condition for resilient support and that the other features of the invention, such as the construction of the means connecting the ends of the beam 1 and mounting it on the bracket 8 are of general application and can be used in other manners not disclosed herein.

While in accordance with the patent statutes,

I have shown and described one embodiment of my, invention, it will be understood that the invention is not limited thereto or thereby but is defined by the appended claims.

What is claimed is: 1. In an aircraft undercarriage, a support tube for supporting an-aircraft wheel, acastor spindle for telescopically receiving said support tube and for securing same on an aircraft, rubber sleeve means having a friction material cover positioned between the telescoped portions of said support tube and said castor spindle for retaining them in alignment, a thrust collar secured to the outer periphery of said support tube at a point remote from the upper end thereof, said castor spindle having an annular support flange formed on its periphery at its lower end, a thrust bearing positioned on the upper surface of said thrust collar, and means securingthe annular support flange of said caster. pindle to said thrust collar with said thrust bearing therebetween for transmittal of load therebetween and so as to permit relative rotational movement, said means comprising a split collar with shoul ders engaging the upper surface of said flange and the lower surface of said thrust collar.

2. In an aircraft undercarriage, a support tube for supporting an aircraft wheel, a castor spindle for telescopically receiving said support tube and for securing same on an aircraft, sleeve means positioned between the telescoped portions of said support tube and said castor spindle for retaining them in alignment, a thrust collar secured to the outer periphery of said support tube, said castor spindle having an annular support flange on its periphery at its lower end, a thrust bearing positioned on the upper surface of said thrust collar, and means securing the support flange of said castor spindle to said thrust collar with said thrust bearing therebetween for transmittal of load therebetween and so as to permit relative rotational movement, said means comprising a split collar with shoulders engaging the upper surface of said flange and the lower surface of said thrust collar.

3. In an aircraft undercarriage, a support tube for supporting an aircraft wheel, a castor spindle for telescopically receiving said support tube and for securing same on an aircraft, rubber sleeve means having a friction material cover positioned between the telescoped portions of said support tube and said castor spindle for retaining them in alignment, said friction material including fabric impregnated with a thixotropic lubricating composition which is adapted to impart a greater kinetic than static coefficient of friction, a thrust collar secured to the outer periphery of said support tube at a point remote from the upper end thereof, said castor spindle having an annular support flange formed on its ROY W. BROWN.

(References on following page) R FEBENQES- 33 3 Number The following references are of record in the file of thls patent. I v 2:348:493 UNITED STATEQ mm'gs 5 2,39%825 N m r Name Pa s 5 37 McElmy qvv-z-y gq-i Jan- 3 1 2 3, M 3 1 J e 1 .1 1 Number -.'--'?--.*:'-fi" "-V'.-

8 -Name pate. -:V-'-':-= S Dowty V July 29, 1941 Parker May 9, 1944. Trader H Feb. 12, 1946 FQREIGN PATENTS Country Date Great Britain w Dec, 17, 1934 

